With the development of touch control technologies, there are more and more applications of an ultrathin screen in a terminal device. However, a touch screen (or a touch control screen or a touch control panel) may show different sensitivity when a terminal device is in different placement states. For example, touch control sensitivity may be low when a smart phone (namely, an example of the terminal device) is horizontally placed on a non-conductive desktop, because the touch screen is in a floating state, and a coupling capacitance between a person and the cell phone ground is small, resulting in that a sensing signal detected by the touch screen could not accurately reflect the coupling capacitance, thereby leading to a reduction in sensitivity of the touch screen.
Therefore, it is necessary to provide a technique that could solve a problem of a reduction of touch control sensitivity when a touch screen is in a floating state.